An electrophotographic image formation device is known to have a developer cartridge that is configured to be attachable to and detachable from an image formation device mainbody (simply referred to as a device “mainbody” in this “BACKGROUND” section). The developer cartridge includes a developer roller that provides a toner supply, for image developing, to electrostatic latent images formed on a photosensitive member. As an example, FIG. 8 of Japanese Laid Open Patent Publication No. 2003-295614 (which corresponds to FIG. 8A of U.S. Pat. No. 6,823,160) shows a configuration in which a developer electrode is electrically connected to a developer roller, and the developer electrode protrudes outside of a developer cartridge. With such a configuration, when the developer cartridge is attached to the device mainbody, the developer electrode comes in contact with a power supply electrode provided at the device mainbody side so that, at the time of printing, a bias voltage is applied via these electrodes to the developer roller from a power supply provided in the device mainbody.
One potential problem with such a configuration is that when the developer cartridge is individually carried around, the developer electrode may interfere with other components and/or become damaged because the electrode protrudes outside of the developer cartridge.